A wide variety of fasteners have been developed for use in an equally wide variety of situations. Devices for use in applying such fasteners are as varied as the fasteners themselves. Recently, in the continuing effort to increase efficiency and productivity, many such devices have been automated.
For example, a number of different fasteners may be used to secure a wall, ceiling or floor to a stud or joist. Fasteners such as screws and nails can now be applied more efficiently using automatic devices. Indeed, automatic hammers, such as that disclosed in U.S. Pat. No. 4,483,474 issued to Nickolich, are increasingly important tools in the construction industry.
Devices such as automatic hammers have generally increased productivity in the construction industry. However, their effective use is still dependant on their individual operators. To ensure proper structural integrity, a nail must be adequately centered over a stud or joist before being driven into a wall, ceiling or floor. Proper location of the nails is dependant solely on the automatic hammer operator.
While automatic hammers allow their operators to drive more nails in a given period of time than can be driven manually, this increased efficiency is at least partially offset by the delay of the operator in properly locating the nails. Many operators attempt to overcome this delay by exercising less care in locating the nails and increasing the number of nails driven. While such a procedure generally ensures that an adequate number of nails are properly secured, it again partially offsets any improved efficiency by the added cost of the excess nails used.
Devices for sensing the presence of studs or joists behind wall, ceiling or floor material are well known in the art. U.S. Pat. No. 4,099,118 issued to Franklin et al discloses such a device and is incorporated herein by reference. Such devices generally detect a stud or joist by utilizing the change in the dielectric constant of the wall, ceiling or floor material caused by the presence of a stud or joist.
However, while such sensors ensure proper nail location, they can create cumbersome and unsafe working environments when used separately with automatic hammers. This problem can be overcome by mounting the sensor directly to the automatic hammer. However, such a device still requires the operator to determine when an individual nail will be driven. As a result, without coordinating the output of the sensor to the operation of the automatic hammer, the full potential of such a device cannot be realized.